A deadly measles outbreak centred on Lancaster County, Pennsylvania — home to one of the largest Amish (a devout, technology-abstaining Christian community) populations in the United States — has killed four people, including two newborns, an 18-year-old, and a 40-year-old woman. With an estimated three-quarters of Lancaster's Amish residents unvaccinated, health workers from the Chester County Health Department are conducting home visits to administer the MMR vaccine, having delivered over 500 doses since the outbreak began, many at kitchen tables in private residences. Public health officials warn the outbreak could persist for six to twelve months, with concerns growing ahead of the school year, as political disputes over the cause of the deaths and mixed messaging from federal health authorities continue to complicate vaccination efforts.